Antenna construction



Aug 9, 1949- H. o. PETERSON ANTENNA CONSTRUCTION Filed July l19, 1945 z2 a z INVENTOR.

m www D@ awo. ww, 0^ mw Patented Aug. 9, 1949 ANTENNA CONSTRUCTIONHarold O. Peterson, Riverhead, N. Y., assgnor to Radio Corporation ofAmerica, a corporation of Delaware Application July 19, 1945, Serial No.605,982

3fGl'aims. (Cl.V Z50-m33)` The present invention relates to short waveantennas.

An object of the present invention is to increase the reliability ofoperation of ultra short wave antennas and associated matching sections.

Another object of the present invention is to decrease the physical sizeof the matching stubs associated with ultra short wave antennas.

A further object of the present invention is the provision of an ultrashort wave antenna which is not subject to losses in efficiency due tomoisture, rain, snow, etc., entering the transformation and matchingstub sections associated with the antenna.

The foregoing objects and others which may appear from the followingdetailed description are obtained by providing, in a balanced antennafed from an unbalanced transmission line, solid dielectric insulatingmaterial in the bazooka or line balance converter coupling thetransmission line to the balanced antenna.

The present invention will be more fully understood by referring to thefollowing detailed description which is accompanied by a drawing whereinreference numerals Il] and identify a pair of opposed arms of a halfwave dipole antenna. To the adjacent ends of arms lll and are connectedthe conductors of a coaxial transmission line TL. Thus inner conductor20 is connected to the inner end of arm and outer sheath 2| is connectedto the inner end of arm In order to electrically free the end of sheath2| from ground, the sheath is surrounded by an outer shell 22 having anelectrical length equal to one quarter of the operating wavelength andconnected to sheath 2| at the end remote from the free end of sheath 2|.Thus, energy unbalanced with respect to ground ilowing along theinterior ci transmission line energizes rods l0, in equal and oppositeinstantaneous polarities. In order to prevent water from rainstorms,rough seas, etc. from iilling up the shell 22 and thus impairing itsoperation, the shell is lled with a solid dielectric material 24. Thedielectric material may be methylmethacrylate, commonly known as Lucite,polystyrene or polyethylene. The solid dielectric material not onlymaintains the electrical efficiency constant at all times but also actsas a supporting means for maintaining the concentric relationshipbetween outer sheath 2| and shell 22. Also since the dielectric material24 extends over the adjacent ends oi dipole arms l0, it acts as asupport to maintain them in concentric endto-end relationship wherebythe radiation pattern of the antenna is maintained constant. Since thedielectric constant of any of the solid dielectrics mentioned above isconsiderably higher than that of the dielectric constant of air, themechanical length of shell portion 22 is shorter than the electricallength, thereby making the structure more compact. It is therefore lesssubject to mechanical damage.

While I have illustrated a particular embodiment of the p-resentinvention, it should be clearly understood that it is not limitedthereto since many modifications may be made in the several elementsemployed and in their arrangement and it is therefore contemplated bythe appended claims to cover any such modifications as fall within thespirit and scope of the invention.

What is claimed is:

l. A short wave antenna including a pair of elongated conductors inend-to-end relationship, a Coaxial transmission line having an innerconductor and an outer sheath conductor, an outer shell having anelectrical length equal to one quarter of the operating wavelength ofsaid antenna surrounding the end of said line and connected to saidsheath at its end remote from the end of the line, each of the adjacentends of said conductors being connected to one of the conductors of saidtransmission line and a low loss solid dielectric material filling thespace between the conductors of said line and the space between saidshell and said sheath, said solid dielectric material extendingoutwardly of the end of said shell and surrounding the adjacent ends ofsaid elongated conductor whereby they are maintained in position.

2. A short wave antenna including a pair of elongated conductors inend-to-end relationship, a coaxial transmission line having an innerconductor and an outer sheath conductor, an outer shell having anelectrical length equal to one quarter of the operating wavelength ofsaid antenna surrounding the end oi said line and connected to saidsheath at its end remote from the end of the line, each of the adjacentends of said conductors being connected to one of the conductors of saidtransmission line and a low loss solid dielectric material lling thespace between said shell and said sheath, said solid dielectric materialextending outwardly of the end of said shell and surrounding theadjacent ends of said elongated conductor whereby they are maintained inposition.

3. A short wave antenna including a pair of elongated conductors inend-to-end relationship, a coaxial transmission line having an innerconductor and an outer conductor, an outer conductive shell coterminouswith said transmission line having an electrical length equal to onequarter of the operating wave-length of said antenna and surrounding theend of said line and connected to said outer conductor at the end ofsaid shell remote from the end of said line, each of the adjacent endsof said elongated conductors being connected to one of the conductors ofsaid transmission line, and a low loss solid dielectric material fillingthe space between the conductors of said line and the space between theouter conductor of said line and said shell and extending outwardly fromthe end of said shell and surrounding the adjacent ends of saidelongated conductors to maintain the relative spacial position of saidinner and outer conductors, said shell and said elongated conductors andsimultaneously to close the end of said transmission line to theexternal atmosphere.

HAROLD O. PETERSON.

4 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,854,255 Green Apr. 19, 19322,111,743 Blumlein Mar. 22, 1938 2,193,017 Bassett Mar. 12, 19402,213,276 Gossel Sept. 3, 1940 2,234,068 Wiseman Mar. 4, 1941 2,249,963Lindenblad July 22, 1941 2,304,210 Scott Dec. 8, 1942 2,322,971Roosenstein June 29, 1943 2,337,556 Hosking Dec. 28, 1943 2,348,919Milton May 16, 1944 2,350,916 Morrison June 6, 1944 2,407,057 CarterSept. 3, 1946 2,411,034 Gluyas Nov. 12, 1946 2,412,867 Briggs Dec. 17,1946

